• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.5
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• pp.23-32
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• 2015

The advanced receiver which can manage inter-cell interference is required to cope with the explosively increasing mobile data traffic. 3rd Generation Partnership Project (3GPP) has discussed network assisted interference cancellation and suppression (NAICS) to improve signal-to-noise-plus-interference ratio (SINR) and receiver performance by suppression or cancellation of interference signal from inter-cells. In this paper, we propose the novel hybrid receiver Full Suppression Cancellation (FSC) to reduce the interference from neighbor cell in backhaul system. The proposed receiver can suppress and cancel the interference by combining Interference Rejection Combining (IRC) with Successive Interference Cancellation (SIC). We perform the system level simulation based on 20MHz bandwidth of 3GPP LTE-Advanced system. Simulation results show that the proposed receiver can improve error rate and throughput of conventional system.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.10
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• pp.45-49
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• 2014

In this paper, the performance of the interference cancellation using multiple receive antennas is evaluated for heterogeneous cellular systems when user association and load balancing problems are optimized for cell edge users. The simulation results show that the interference cancellation method remarkably improves the rate performance of load-balanced cells.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.8A
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• pp.743-751
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• 2010

OFDMA femtocell becomes an effective solution to support indoor high data rate services instead of the macrocell systems. Although the advantage of the femtocell, the co-channel interference between the femocell and the macrocell is the most significant problem that reduces the system performance. Macrocell users who have no permission to access the femtocell suffer from interference of the downlink transmission of femtocell. Therefore, the femtocell should use transmission power as small as possible to reduce interference to macrocell users. In this paper, we define the margin adaptive power allocation problem for the femtocell and propose a heuristic power allocation algorithm to solve the problem. Simulation results show the performance of the proposed algorithm.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.11
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• pp.1288-1296
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• 2012

A candidate hybrid satellite and terrestrial network architecture, MSS/ATC(Mobile Satellite Service/Ancillary Terrestrial Component), is proposed for utilizing efficiently the exist MSS bands. Studies on the adjacent channel interference from the existing terrestrial mobile services and MSS/ATC itself are important to allocate a new ATC service frequency in MSS band. In this paper, we have analyzed the minimum permission power of terrestrial base station and the capacity loss with parameters of ACIR, number of MS(mobile Station) and MES(Mobile Earth Station) in uplink, and also, the capacity performance based on 1 beam and 1 cell assumption for MSS/ATC in downlink. The ACIR requirements are estimated in two MSS/ATC frequency allocation scenarios for 5 MHz and 10 MHz guard band to share spectrum with adjacent systems, and according to these ACIR requirements the service coverage and the receiver filter for ATC system should be designed in near future.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.3 s.357
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• pp.51-60
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• 2007

Cellular OFDMA systems may suffer from various amounts of inter-cell interferences according to subcarriers. If it is possible to estimate the interference level of each subcarrier, the performance can be improved by adjusting the magnitude of channel decoder input signals inversely proportional to the interference amounts. While conventional cellular systems prefer to use interference averaging techniques for mitigating inter-cell interferences, this paper shows that localizing inter-cell interferences to the reduced number of subcarriers can significantly improve the system performance assuming thatinterference estimation can be employed. If interference estimation is not used, it is more favorable to use interference averaging techniques to avoid excessive interference levels to certain subcarriers. On the other hand, if interference estimation can be employed, interference localization is more beneficial than interference averaging.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.9
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• pp.1057-1063
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• 2007

To analyze the performance of mobile communication systems, the exact information of the carrier-to-interference ratio is important. Under the presence of an interferer in a cell, the carrier-to-interference ratio of the receiver is determined by the ratio between the informer-receiver distance$(d_0)$ and the receiver-interferer distance$(d_1)$. In this paper, we derive the carrier-to-interference distribution based on $d_0/d_1$ values using the geometric relation among the informer, interferer and receiver, and confirm its exactness using the simulation result. We also apply the derivation result to a system with the adjacent channel interference, and analyze the outage probability.

• Journal of the Institute of Convergence Signal Processing
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• v.17 no.1
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• pp.46-52
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• 2016

LTE-Advanced system consisting of the number of cells in the cellular environment because it is built to allow efficient use of limited frequency resources of adjacent cell interference avoidance should be considered. Transition services in accordance with the development of the mobile communication technology, wireless multimedia content from voice-centric mobile communications services and causing a lot of mobile data traffic, such as smart phones and tablet terminals spread of a data-driven surge in mobile data traffic base stations in urban areas by increasing became a reality that can not be prevented. In this paper, we propose a new Hybrid resource allocation technique for improving the performance of the cell boundary and analyzed the performance of the proposed new techniques to perform the simulation using LTE-Advanced system level simulator based on 19cell of cellular system model.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8A
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• pp.829-837
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• 2008

A cellular system with fixed relays is considered to be a technology that can support high data transmission service to wide areas. However, either inter-cell interference or inter-sector interference that can be produced by adding relays to the cellular system with fixed relays does not guarantee high link performance to deteriorate function, so that resource allocation for avoidance of interference is very much important. In the paper, the cellular system performance with repeater relay has been compared with the cellular system performance with relay, and cell coverage expansion at the use of relay repeater has been compared. To compare, this paper has suggested resource allocation method to avoid inter-cell interference and inter-sector interference at installation of fixed relay on the cellular system. The proposed method can allocate different frequency resources on adjacent base stations and relays to reduce interference and to expand high data transmission area, and all of frequency bands are used at each sector to elevate efficiency of the frequency when base stations and relays operate simultaneously.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.3
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• pp.122-137
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• 2007

In this paper, compatibility between different radio services or systems is analyzed when they are in adjacent band or co-channel. The first step of the compatibility analysis is establishing an interference scenario. And an interference pobability from an interfering transmitter to a victim receiver is calculated by means of Monte-Carlo simulation techniques. Then the calculated result is compared with the predefined interference criteria, maximum permissible interference probability and we can determine compatibility in accordance with the active interferer density, channel bandwidth, cell radius, distance between interfering transmitter and victim receiver, and duty cycle. It is assumed that Propagation modes are the free space model and extened Hata model.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.3 s.345
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• pp.32-38
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• 2006

In this paper, an intercell interference (ICI) reduction technique is proposed for OFDM-based cellular systems using the concept of virtual multiple antenna where multiple antenna techniques are performed on a set of subcarriers, not on the actual antenna array. The proposed technique is especially effective for user terminals with a single antenna at cell boundary in fully-loaded OFDM cellular systems with a frequency reuse factor equal to 1. Proposed ICI reduction techniques developed for SISO and MISO environments are shown to be robust to symbol timing offsets and efficient for various cell environments by adjusting group size depending on the number of adjacent cells. Also, the concept of a virtual signature randomizer (VSR) is introduced to improve channel separability in the virtual MIMO approach. It is shown by simulation that the proposed techniques are effective in reducing ICI and inter-sector interference compared with the conventional methods.